1. Field of the Invention
The present invention relates to a switch, particularly relates to a push-push switch for switching heavy-current.
2. Description of the Related Art
It is known that variable and fixed contacts of a conventional type switch, particularly a push-push switch for switching heavy-current are deformed or worn by arc discharge by switching (turning on or off) heavy-current of each contact.
Therefore, the variable and fixed contacts have been variously configured to prevent deformation or abrasion, however, in any case, they have complex structures or high-priced contact material to prevent deformation and abrasion is used.
As the conventional type switch is formed by a body in which a mechanism having complex structure of the variable and fixed contacts is housed, the body is large-sized.
As described above, as the conventional type switch is a switch for switching heavy-current, the structure of the variable and fixed contacts is complex and each contact is formed by a member using high-priced contact material which endures switching heavy-current.
As a result, there is a problem that the body housing the variable and fixed contacts is large-sized and as they are formed by a contact member using high-priced contact material, the cost of the switch is increased and a small-sized and low-priced switch is desired.
A switch according to the invention is made to solve the abovementioned problems and the object is to provide a small-sized and low-priced switch.
The switch according to the invention is provided with a body, an operating shaft housed in the body, a moving contact arranged in the body so that it is moved in an axial direction of the operating shaft, a pair of fixed terminals arranged in the body so that they are located over the moving contact and a first coil spring housed on the side of a bottom wall of the body so that it presses the moving contact upward in the axial direction of the operating shaft and is characterized in that the moving contact is provided with first and second contacts provided at both ends, the first contact is made of noble metal, a pair of fixed terminals are respectively provided with a fixed contact, the first and second contacts are touched to each fixed contact by pressure on the moving contact by the first coil spring, touching an end of the operating shaft to the moving contact by moving the operating shaft downward in the axial direction, and the first contact of the moving contact is separated from the fixed contact of the fixed terminal earlier than the second contact by further pushing down the operating shaft against the pressure of the first coil spring and the first contact of the moving contact is touched to the fixed contact of the fixed terminal later than the second contact by the pressure of the first coil spring by returning the operating shaft.
According to such a configuration, as the first contact made of noble metal is earlier separated from the fixed contact and is later touched to the fixed contact, high-priced material is required for only the first contact on one side and the stable and long life can be achieved even if the low-priced heavy-current switch is operated.
The switch according to the invention is also characterized in that the moving contact is formed by a flat plate and is composed of a base substantially in a center and first and second arms at both ends, the first arm in which the first contact is provided is bent downward in a bent part in relation to the base and the first and second contacts are touched to each of the fixed contacts by inclining the base in relation to the fixed contact and most approaching the bent part to an end of the operating shaft by the pressure of the first coil spring on the base of the moving contact.
According to such a configuration, as the moving contact is formed by a flat plate and is formed by bending a part, the configuration is simple and the low-priced moving contact is acquired.
The switch according to the invention is also characterized in that a hole is formed in a center of the moving contact, the second coil spring pierces the hole of the moving contact, the second coil spring is arranged coaxially with the first coil spring inside the first coil spring and the second coil spring presses the operating shaft upward in the axial direction of the operating shaft.
According to such a configuration, as the first coil spring and the second coil spring are coaxially arranged and the second coil spring for pressing the operating shaft pierces the hole of the moving contact, space can be effectively utilized and the switch can be small-sized.
The switch according to the invention is also characterized in that a strut perpendicularly extended from the bottom wall is provided on the bottom wall of the body, the first and second coil springs are provided along the strut and the operating shaft is arranged at an end of the strut so that the operating shaft can be moved upward or downward in the axial direction.
According to such a configuration, the first and second coil springs and the operating shaft can be easily positioned by the strut.
The switch according to the invention is also provided with a body, an operating shaft housed in the body, a moving contact arranged in the body so that the moving contact is moved in an axial direction of the operating shaft, a pair of fixed terminals arranged in the body so that they are positioned over the moving contact and a first coil spring housed on the side of a bottom wall of the body so that it presses the moving contact upward in the axial direction of the operating shaft and is also characterized in that the body is composed of an upper case and a lower case, the lower case has opposite side walls, a pair of opposite convexes are formed on sides of each open end of the side walls, the moving contact pressed by the first coil spring is temporarily tacked in the lower case by fitting both ends of the moving contact to a pair of convexes, the fixed terminal is attached to the lower case from the upside of the moving contact, fitting between one of a pair of convexes and the moving contact is released by elastically pressing the fixed terminal on the moving contact against the pressure of the first coil spring, the upper case covers the lower case from a side of the open end, an end of the operating shaft touches to the moving contact by moving the operating shaft downward in the axial direction, and the moving contact is separated from the fixed terminal by further pushing down the operating shaft against the pressure of the first coil spring and the moving contact is touched to the fixed terminal by the pressure of the first coil spring by returning the operating shaft.
According to such a configuration, in an assembly process, the first coil spring and the moving contact are temporarily tacked in the lower case and the efficiency of assembly can be enhanced.